WattMaster WCC II - Manual (Page 113)

Section 3: Screen Descriptions
WCC II Operator’s Guide
Operator Interfaces 3-81
State
There are two messages which appear under this heading. The fi rst
one is the On/Off message the user enters on the Global Binary
Screen. The second will be one of the following messages which
describe the current status of the global binary value.
ON - The binary global is ON.
OFF - The binary global is OFF.
DUTYCYC - The binary global is OFF, because it has
been overridden by the duty cycle program.
SHED - The binary global is OFF, because it has
been overridden by the shed/restore
program.
OVR - The binary global is forced ON and OFF
due to a command on the override screen.
Alarm Time
The ECC/WCC II system has the capability of alarming if the
value of a binary global is either ON or OFF. The time that the
alarm occurred is shown here.
The alarms for global binary values do not appear on the Alarm
Summary Screen. However, if a global alarm is active, the alarm
class will appear on the Main Menu after the “Active alarms in
classes:” statement.
Acknowledge Alarms
The global binary alarms are acknowledged from the Global
Binary Summary Screen by moving the cursor to the active alarm
and pressing
>. If the global binary value has returned to
normal, the alarm message will be cleared from the screen. It can
take up to 30 seconds before the alarm is cleared from the screen.
The ECC/WCC II can generate the ON or OFF value of the global
binary using either the Combinatorial, Compare, or Alarm mode
of operation.
The Combinatorial mode has the capability of generating the
ON or OFF value of the binary global using “and/or” logic. For
example, binary global #1 (GB1) can be programmed to be ON
if the outside air temperature is above 60 ºF, the building is in the
day mode, and the chilled water pump is running. The ECC/WCC
II system could then be programmed to turn on a chiller whenever
GB1 is ON. The mode used to generate the ON/OFF value of the
binary global using “and/or” logic is called Combinatorial because
several statements are combined together to determine the ON or
OFF value of the binary global.
The Compare Screen allows the ECC/WCC II system to do “greater
than/less than” logic. The ON or OFF value of the binary global is
determined by one numerical value being [equal to], [greater than],
[greater than or equal to], [less than], or [less than or equal to]
another numerical value. For example, the ECC/WCC II system
could monitor the enthalpy (total heat content) of the outside air
and the return air and select the air stream with the lowest heat
content to be used for cooling. The Compare Screen could be
used to cause binary global #2 (GB2) to go ON if the outside air
enthalpy is less than the return air enthalpy, indicating that outside
air should be used for cooling. The ECC/WCC II system could
then be programmed to open the outside air damper and lose the
return air damper when GB2 is ON.
The Alarm mode causes the binary global to generate an ON or
OFF value based on either an active or non-active alarm that has
been either acknowledged or not acknowledged.